/* $Id: PathCallParamRule.java 467222 2006-10-24 03:17:11Z markt $
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.tomcat.util.digester;

import org.xml.sax.Attributes;

/**
 * <p>
 * Rule implementation that saves a parameter containing the
 * <code>Digester</code> matching path for use by a surrounding
 * <code>CallMethodRule</code>. This Rule is most useful when making
 * extensive use of wildcards in rule patterns.
 * </p>
 * 
 * @since 1.6
 */

public class PathCallParamRule extends Rule {

	// ----------------------------------------------------------- Constructors

	/**
	 * Construct a "call parameter" rule that will save the body text of this
	 * element as the parameter value.
	 * 
	 * @param paramIndex
	 *            The zero-relative parameter number
	 */
	public PathCallParamRule(int paramIndex) {

		this.paramIndex = paramIndex;

	}

	// ----------------------------------------------------- Instance Variables

	/**
	 * The zero-relative index of the parameter we are saving.
	 */
	protected int paramIndex = 0;

	// --------------------------------------------------------- Public Methods

	/**
	 * Process the start of this element.
	 * 
	 * @param namespace
	 *            the namespace URI of the matching element, or an empty string
	 *            if the parser is not namespace aware or the element has no
	 *            namespace
	 * @param name
	 *            the local name if the parser is namespace aware, or just the
	 *            element name otherwise
	 * @param attributes
	 *            The attribute list for this element
	 * 
	 */
	public void begin(String namespace, String name, Attributes attributes)
			throws Exception {

		String param = getDigester().getMatch();

		if (param != null) {
			Object parameters[] = (Object[]) digester.peekParams();
			parameters[paramIndex] = param;
		}

	}

	/**
	 * Render a printable version of this Rule.
	 */
	public String toString() {

		StringBuffer sb = new StringBuffer("PathCallParamRule[");
		sb.append("paramIndex=");
		sb.append(paramIndex);
		sb.append("]");
		return (sb.toString());

	}
}
